Marathon: Durandal

Grab a friend who has it or check the recent achievers and message someone (EDIT: Not me, as i am busy and have little time to play anymore) who has it. Host a multiplayer match , Thunderdome, no time limit, 5 kill limit, rockets only. Then just go wild.

IMPORTANT: make sure any content packs are turned off, i've figured this one out after some people havn't been able to get it.

If you absolutely cannot find anyone to do this achievement with (since the game is pretty dead), it's possible to do it on your own with a second controller, though it's a much lengthier process.

The way you do this is to create a new local Xbox account with the name 'hippieman', the username of one of the developers of the port. As soon as you boot up the game with that account, the achievement will be unlocked immediately. This was confirmed by hippieman himself in a reddit post.

After that you're going to want to upgrade the local account to an Xbox Live Gold account (a 2 day trial will work). Once that's done, boot up the game and sign into both the dummy account with the achievement and your personal account. Start a private match over Xbox Live with whatever settings you choose. Simply play out the match by killing the idle dummy account. After the match ends, the achievement should unlock on your account!

I initially tried doing it locally, but it didn't unlock, so it must be done over Xbox Live. It's all a very long process but it works if you can't find anyone to get the achievement from.

This guide builds off of MTN DEWRIT0S’s guide, so be sure to read that one first and if you thumbs up this guide, thumbs up their guide as well.

If you’re like me and bought Marathon when it first came out like three 360s ago, “hippieman” will only have access to the trial version of Marathon, and will not be able to unlock achievements. Which blows, but there’s a way around this! You’ll need 2 controllers.

Sign into your main account on controller 1. Start up Marathon. After getting to the main menu, sign into hippieman on controller 2. The achievement will pop on the hippieman account. MAKE SURE YOUR MAIN ACCOUNT IS STILL SIGNED IN! If you try to do this with one controller by signing out of your main account while Marathon is running then signing into hippieman, the achievement will unlock for hippieman but will be glitched and won’t count.

Now you can join Xbox Live with hippieman and follow the rest of MTN DEWRIT0S’s guide.